Differences within categories:
This idea is based on a factor that differentiates one weapon from another within the same category (Swords,Bows,Orbs)
Different characteristics that differentiate them such as the attack speed and the basic damage enhancer of the weapon, as well as special uses in certain equipment.
Examples:
Taking stats as a powered base depending on the weapon.
Wide Sword has: 35% Attack speed / 88% Damage power
Cheese Sword has: 67% Attack speed / 35% Damage power
Depending on what bow is, it'll have a counter effect. (Including different attack speed)
> Extra damage against flying enemies
> Piercing arrows
And those are just a few examples.

The Cursed Crystals and the fallen
Cursed Items:
This idea is based on the possibility of obtaining cursed Items in the game, Items that are very powerful but have handi caps such as "this object is more expensive to repair" these could be found in some área type "Temple of the fallen naica" with ancient and powerful enemies.
The fallen temple:
An ancient temple already forgotten and cursed by the former gods of naica.